STRING* filename = "#25";

        [...]

	OPENFILENAME ofd;
	char buf[256];
	FillMemory(&ofd,sizeof(ofd),0);
	FillMemory(buf,256,0);
	
	ofd.Flags=OFN_PATHMUSTEXIST|OFN_FILEMUSTEXIST|OFN_NOCHANGEDIR;
	ofd.lStructSize=sizeof(ofd);
	ofd.hwndOwner=hWnd;
	ofd.lpstrFilter	="Portable Network Graphic\0*.png\0\0";
	ofd.lpstrInitialDir = _chr(""); //work_dir
	ofd.lpstrFile=buf;
	ofd.nMaxFile=255;	
	ofd.lpstrTitle="Lade eine Levelbitmap";
	if (GetOpenFileName(&ofd))
	{
		str_cpy(filename, ofd.lpstrFile);
	}